The present invention relates to novel 1-[1-(hetero)aryl-1-perhydroxyalkylmethyl]-piperazine compounds which are tachykinin receptor antagonists and to medicaments containing these compounds. Furthermore, the invention relates to a process for preparing the novel piperazine compounds and intermediate products of this process.
The tachykinins include the naturally-occurring neuropeptides substance P, neurokinin A and neurokinin B. The tachykinins act as agonists of receptors occurring in larger mammals and humans, such as the neurokinin (=NK)-1 receptor, the NK-2 receptor and the NK-3 receptor. Artificially prepared compounds which are tachykinin receptor antagonists are usually classified according to their relative ability to bind to one or more of the aforementioned three receptor subtypes. In the physiological process the tachykinins play e.g. an important part in the transmission of pain, emesis, neurogenic inflammations, bladder inflammation, inflammatory joint diseases or asthmatic complaints.
Inter alia, piperazine derivatives which act as antagonists to the NK-2 receptor are already known from published European Patent application no. EP 474,561.
Further piperazine derivatives which can act as antagonists to tachykinin receptors are known from published PCT Patent application no. WO 96/10568.
It was an object of the present invention to provide novel active substances having properties antagonistic to tachykinin receptors and an improved activity profile.
Another object of the invention is to provide new active compounds which are suitable for treating peripheral disorders.
A particular of object of the invention was to provide active compounds which are useful to treat functional and inflammatory disorders of the gastrointestinal tract.
These and other objects are achieved in accordance with the present invention by providing a compound corresponding to the formula I: 
wherein
A is naphthyl, phenyl optionally substituted by hydroxy, mono- or bicyclic heteroaryl or C3-6-alkenyl optionally substituted by phenyl,
Z is a subgroup corresponding to the formula 
wherein
R1 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R2, R3, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R2 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R3, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R3 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R4 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R3 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R5 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R3 and R4, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
k is 0 or 1,
l is 0 or 1,
m is 0 or 1 and
n is 0 or 1,
R6 is halogen or hydrogen, and
R7 is halogen or hydrogen,
or a physiologically compatible acid addition salt thereof.
In accordance with a further aspect of the invention, the objects are achieved by providing a method of inhibiting a functional or inflammatory disorder of a lower intestinal tract of a mammal which involves increased sensitivity to pain or impaired stool passage in the colon region, said method comprising administering to said mammal a pharmaceutically effective amount of a piperazine compound as described above.
In yet another aspect of the invention, the objects are achieved by providing a process for the preparation of a compound corresponding to formula I: 
wherein
A is naphthyl, phenyl optionally substituted by hydroxy, mono- or bicyclic heteroaryl or C3-6-alkenyl optionally substituted by phenyl,
Z is a subgroup corresponding to the formula 
wherein
R1 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R2, R3, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R2 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R3, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R3 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R4 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R3 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4--alkylene,
R5 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R3 and R4, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
k is 0 or 1,
l is 0 or 1,
m is 0 or 1 and
n is 0 or 1,
R6 is halogen or hydrogen, and
R7 is halogen or hydrogen,
or a physiologically compatible acid addition salt thereof, said process comprising reacting a compound of formula II: 
wherein R6 and R7 have the above meanings,
with a compound of formula III:
Axe2x80x94B(OH)2xe2x80x83xe2x80x83III
wherein A has the above meaning,
and with a compound of formula IV: 
wherein R1, R2, R3, R4, R5, k, l, m und n have the above meanings, and
optionally acylating a resulting compound of Formula I,
wherein at least one substituent selected from R1, R2, R3, R4 and R5 is hydrogen, in the subgroup Z by reacting with a compound corresponding to formula VIII:
R8xe2x80x94COOHxe2x80x83xe2x80x83(VIII)
wherein R8 is a straight-chain or branched alkyl with 1 to 3 carbon atoms, or
optionally carbonylating or thiocarbonylating a resulting compound of Formula I, wherein at least two substituents selected from R1, R2, R3, R4 and R5 are hydrogen, in the subgroup Z by reacting the compound of formula I with a reactive carbonyl- or thiocarbonyl synthesis equivalent, or optionally converting a resulting compound of Formula I, wherein at least two substituents, selected from R1, R2, R3, R4 and R5 are hydrogen, to a 5- or 6-member ring derivative bridged by methylene and optionally substituted by lower alkyl or C4-5-alkylene by reacting the compound of Formula I in the subgroup Z with a di-lower alkylketone or a C5-6-cycloalkylketone, and
optionally converting compound of Formula I into a corresponding acid addition salt, or
optionally converting an acid addition salt into a free compound of Formula I.
A still further aspect of the invention involves the provision of a compound compound corresponding to formula II: 
wherein
R6 is halogen or hydrogen, and
R7 is halogen or hydrogen.
It has now been found, surprisingly, that a group of novel 1-[1-(hetero)aryl-1-perhydroxyalkylmethyl]-piperazine compounds is distinguished by properties antagonistic to tachykinin receptors, in particular to NK-2 receptors, and has a marked action component directed at the peripheral region. Accordingly, the group of compounds according to the invention appears particularly suitable for the treatment of peripheral disorders in which tachykinins, in particular neurokinin A, participate as transfer agents, for example for the treatment and/or prophylaxis of functional and inflammatory disorders of the gastrointestinal tract. The designation (hetero)aryl is to be understood within the scope of the present invention as possibly comprising both aryl and heteroaryl radicals.
The invention thus relates to novel 1-[1-(hetero)aryl-1-perhydroxyalkylmethyl]-piperazine compounds of the general formula I, 
wherein
A is naphthyl, phenyl optionally substituted by hydroxy, mono- or bicyclic heteroaryl or C3-6-alkenyl optionally substituted by phenyl,
Z stands for a subgroup of the general formula 
wherein
R1 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R2, R3, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R2 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R3, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R3 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R4 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R4 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R3 and R5, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
R5 is hydrogen or lower alkanoyl, or together with another substituent, selected from the group consisting of R1, R2, R3 and R4, may form a 5- or 6-member ring bridged by carbonyl, thiocarbonyl or by methylene optionally substituted by lower alkyl or C4-5-alkylene,
k is 0 or 1,
l is 0 or 1,
m is 0 or 1,
n is 0 or 1,
R6 is halogen or hydrogen, and
R7 is halogen or hydrogen,
and physiologically compatible acid addition salts of compounds of Formula I. Furthermore, the invention also includes pharmaceutical compositions containing the compounds of Formula I. Additionally, the invention relates to a process for the preparation of compounds of Formula I and intermediate products of this process.
Whenever in the compounds of Formula I or in other compounds described within the scope of the present invention substituents are or contain lower alkyl, these may each be straight-chain or branched and possess 1 to 4 carbon atoms. Whenever substituents in compounds of Formula I are halogen, fluorine, chlorine or bromine are suitable. Chlorine is preferred. Where substituents contain lower alkanoyl, this may be straight-chain or branched and possess 2 to 4 carbon atoms. Acetyl is the preferred lower alkanoyl.
The subgroup A preferably stands for monocyclic heteroaryl. Suitable monocyclic heteroaryls are in particular thiophene, furan and pyrrole. Thiophene and furan are preferred. Where A stands for bicyclic heteroaryl, in particular benzothiophene, benzofuran and indole are suitable. Where A stands for C3-6-alkenyl optionally substituted by phenyl, the alkenyl chain may be straight-chain or branched and stands in particular for 1-alkenyl.
Where a substituent covered by the subgroup Z from the group consisting of R1, R2, R3, R4 and R5 together with another substituent selected from this group stands for a 5- or 6-member ring bridged by methylene optionally substituted by lower alkyl or C4-5-alkylene, in particular 5- or 6-member rings bridged by methylene, 1,1-dimethylmethylene, 1,1-spiro-tetramethylene-methylene or 1,1-spiro-pentamethylene-methylene are suitable. Corresponding 5- or 6-member rings bridged by carbonyl are to be regarded as cyclic carbonates. Corresponding 5- or 6-member rings bridged by thiocarbonyl are to be regarded as cyclic thiocarbonates. k preferably stands for 1. n preferably stands for 0. Z thus preferably represents an optionally substituted 1,2-diol radical, a 1,2,3-triol radical or a 1,2,3,4-tetrol radical. The carbon atoms bearing the substituents R1, R2, R3 and R4 are asymmetric and may each occur in two different configurations. Due to this, Z may occur in several stereoisomeric forms. The present invention also covers, in addition to the compounds of Formula I which contain mixtures of stereoisomeric forms of the subgroup Z, compounds of Formula I in which isomerically pure subgroups Z are contained. Preferred subgroups Z are xylo-1,2,3,4-tetrahydroxybutyl, lyxo-1,2,3,4-tetrahydroxybutyl, arabino-1,2,3,4-tetrahydroxybutyl, threo-1,2,3-trihydroxypropyl, erythro-1,2,3-trihydroxypropyl and glycero-1,2-dihydroxyethyl. The carbohydrates selected from the D-series of the carbohydrates on which the subgroups Z are based mostly produce the most beneficial results. Diastereomerically pure subgroups Z are preferred.
Particularly preferred compounds of Formula I are selected from the group consisting of
N-((2S)-2-(3,4-dichlorophenyl)-4-{4-[(2S,3R,4R)-2,3,4,5-tetrahydroxy-1-(3-thienyl)pentyl]-1-piperazinyl}butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2S)-2,3-dihydroxy-1-(2-furyl)propyl]-1-piperazinyl}-butyl)-N-methylbenzamide; (2S)-2-(acetyloxy)-3-{4-[(3S)-4-[benzoyl(methyl)amino]-3-(3,4-dichlorophenyl)butyl]-1-piperazinyl}-3-(2-furyl)propylacetate;
N-[(2S)-2-(3,4)-dichlorophenyl)-4-(4-{2-furyl[(4S)-2-oxo-1,3-dioxolan-4-yl]methyl}-1-piperazinyl)butyl]-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(1S,2R)-2,3-dihydroxy-1-(3-thienyl)propyl]-1-piperazinyl}-butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2S)-2,3-dihydroxy-1-(3-furyl)propyl]-1-piperazinyl}-butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2R,3R,4R)-2,3,4,5-tetrahydroxy-1-(3-thienyl)pentyl]-1-piperazinyl}butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2S,3R,4R)-2,3,4,5-tetrahydroxy-1-(2-furyl)pentyl]-1-piperazinyl}-butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2R)-2,3-dihydroxy-1-(3-thienyl)propyl]-1-piperazinyl}-butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2R,3S,4S)-2,3,4,5-tetrahydroxy-1-(3-thienyl)pentyl]-1-piperazinyl}butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[2S,3R,4R)-2,3,4,5-tetrahydroxyacetyl-1-(3-thienyl)pentyl]-1-piperazinyl}-butyl)-N-methylbenzamide;
N-((2S)-2-(3,4-dichlorophenyl)-4-{4[(2S,3R)-2,3,4-trihydroxy -1-(3-thienyl)butyl]-1-piperazinyl}-butyl)-N-methylbenzamide and
N-((2S)-2-(3,4-dichlorophenyl)-4-{2-furyl[(4S)-2-thioxo-1,3-dioxolan-4-yl]methyl}-1-piperazinyl)-butyl]-N-methylbenzamide.
The compounds of Formula I and their acid addition salts may be prepared by reacting a compound of the general Formula II 
wherein R6 and R7 have the above meanings, with a compound of the general formula III,
Axe2x80x94B(OH)2xe2x80x83xe2x80x83III
wherein A has the above meaning, and with a compound of the general formula IV, 
wherein R1, R2, R3, R4, R5, k, l, m und n have the above meanings, and then if desired acylating a resulting compound of Formula I, wherein at least one substituent, selected from R1, R2, R3, R4 and R5, is hydrogen, in the subgroup Z by reacting with a compound of the general formula VIII,
R8xe2x80x94COOHxe2x80x83xe2x80x83(VIII)
wherein R8 has the meaning straight-chain or branched alkyl with 1 to 3 carbon atoms, or then if desired carbonylating or thiocarbonylating respectively a resulting compound of Formula I, wherein at least two substituents, selected from R1, R2, R3, R4 and R5, are hydrogen, in the subgroup Z by reacting with a reactive carbonyl or thiocarbonyl synthesis equivalent, or reacting a resulting compound of Formula I, wherein at least two substituents, selected from R1, R2, R3, R4 and R5, are hydrogen, in the subgroup Z by reacting with a di-lower alkylketone or a C5-6-cycloalkylketone to form a 5- or 6-member ring derivative bridged [by] methylene optionally substituted by lower alkyl or C4-5-alkylene, and converting a resulting compound of Formula I if desired into its acid addition salt or converting an acid addition salt into a free compound of Formula I.
The reaction can be carried out in known manner under the conditions of a boronic Mannich reaction (cf. e.g. N. A. Petasis et al., Journal of the American Chemical Society 120 (1998) 11798-11799, WO 98/00398 or WO 00/24510). According to this, a compound of Formula II can be reacted in the manner of a one-pot reaction with a boronic acid of Formula III and a carbohydrate of Formula IV which is optionally protected by suitable protective groups in a solvent which is inert under the reaction conditions. Suitable protective groups for carbohydrates are known per se, for example, from J. A. W. McOmie, xe2x80x9cProtective Groups in Organic Chemistryxe2x80x9d, Plenum Press, 1973, or from T. W. Green, P. G. Wuts, xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d, Wiley and Sons, 1999. Suitable solvents are dipolar-protic organic solvents such as lower alkanols, for example straight-chain or branched C1-4-alkanols, preferably ethanol, or mixtures of these aforementioned solvents with water or with dipolar-aprotic solvents such as lower haloalkanes, preferably dichloromethane, are suitable. Suitable reaction temperatures are between room temperature and the boiling point of the solvent or of the solvent mixture. The compounds of Formulae II, III and IV may preferably be combined in succession in this given sequence. Likewise, it is also possible, first to combine a compound of Formula II with a compound of Formula IV and then with a compound of Formula II. The chiral centre bearing the subgroups A and Z newly produced by this coupling reaction in compounds of Formula I is usually formed with a very high degree of diastereo-control as an xe2x80x9cantixe2x80x9d product.
The compounds of Formula I which bear at least one free hydroxyl group in the subgroup Z may if desired then also be reacted with compounds of Formula VIII, whereby the free hydroxyl groups of the subgroup Z are acylated. Usually under these circumstances peracylation of the free hydroxyl groups of the subgroup Z takes place. The acids of Formula VIII or their reactive derivatives may be used as acylation agents. In particular acid anhydrides and acid halides are suitable reactive derivatives. The acylation may be carried out in an organic solvent which is inert under the reaction conditions, preferably at temperatures between xe2x88x9220xc2x0 C. and room temperature. Suitable solvents include in particular aromatic hydrocarbons such as benzene or toluene, cyclic or open-chain di-lower alkyl ethers such as diethyl ether, tetrahydrofuran (=THF) or dioxane, partially halogenated lower hydrocarbons such as dichloromethane or mixtures of these solvents. Where an acid anhydride or an acid halide of the acids of Formula VIII is used as acylation agent, the acylation may expediently take place in the presence of an acid-binding reagent. Suitable acid-binding reagents are non-nucleophilic organic bases soluble in the reaction mixture, such as pyridine, triethylamine or 4-dimethylaminopyridine. Organic bases used in excess can simultaneously also be used as solvents.
The compounds of Formula I which carry at least two free hydroxyl groups in the subgroup Z may if desired, after their preparation described above, also be reacted with a reactive carbonyl- or thiocarbonyl-synthesis equivalent, instead of a reaction with compounds of Formula VIII, whereby the subgroup Z can be carbonylated or thiocarbonylated respectively. The reaction can take place in known manner. For example, a compound of Formula I can be reacted in an organic solvent which is inert under the reaction conditions. Suitable reactive carbonyl synthesis equivalents are for example phosgene or substances which react like phosgene, such as bis-(trichloromethyl)carbonate (=triphosgene), trichloromethyl chloroformate (=diphosgene) or in particular carbonyldiimidazole. Preferably N,Nxe2x80x2-thiocarbonyldiimidazole is suitable as reactive thiocarbonyl synthesis equivalent. Expediently an acid-binding reagent may be added to the reaction mixture. Suitable acid-binding reagents are the acid-binding reagents given above for the reaction of compounds of Formula I with compounds of Formula VIII. Suitable reaction temperatures are between about xe2x88x9220xc2x0 C. and room temperature.
The compounds of Formula I which carry at least two free hydroxyl groups in the subgroup Z may if desired, after their preparation described above, instead of a reaction with compounds of Formula VIII or instead of a reaction with reactive carbonyl or thiocarbonyl synthesis equivalents, also be reacted with a di-lower alkyl ketone or a C5-6-cycloalkyl ketone in the subgroup Z, to produce a 5- or 6-member ring derivative bridged [by] methylene optionally substituted by lower alkyl or C4-5-alkylene. Preferably acetone is suitable as di-lower alkyl ketone. Preferably cyclopentanone and cyclohexanone are suitable as C5-6-cycloalkyl ketones. Where compounds of Formula I are to be prepared in which the substituents contained in the subgroup Z R1, R2, R3, R4 and/or R5 have meanings other than hydrogen, the point of departure is preferably carbohydrate compounds of Formula IV which contain free hydroxyl groups at least in xcex1-position to the aldehyde function. It is beneficial to start with compounds of Formula IV wherein R1, R2, R3, R4 and R5 are hydrogen. The free hydroxyl groups may if desired then be acylated, carbonylated, thiocarbonylated or reacted with a suitable ketone in the above manner.
The compounds of Formula II are novel compounds which are advantageously suitable as intermediate products for the preparation of novel active substances, for example for the preparation of the compounds of Formula I, which are antagonistic to tachykinin receptors.
The compounds of Formula II can be prepared by reacting a compound of the general formula V, 
wherein R6 and R7 have the above meanings and X stands for halogen, in particular for iodine, with a protected piperazine derivative of the general formula VI, 
wherein SG stands for a cleavable protective group, in particular for tert. butoxycarbonyl, and subsequently cleaving off the protective group SG again in known manner. The reaction can be carried out in an organic solvent which is inert under the reaction conditions, such as an aromatic hydrocarbon, in particular toluene, or in a cyclic or open-chain di-lower alkyl ether, in particular THF, or preferably in a mixture of the aforementioned solvents and in the presence of a base. Suitable bases are non-nucleophilic organic nitrogen bases such as tertiary lower alkylamines, for example triethylamine. Suitable reaction temperatures are between 50xc2x0 and 100xc2x0 C., preferably approximately 70xc2x0 to 90xc2x0 C.
Compounds of Formula V can be prepared by reacting compounds of the general formula VII, 
wherein R6 and R7 have the above meanings, in known manner with an alkali metal halide of the general formula MX, wherein M stands for an alkali metal, in particular sodium, and X has the above meaning and stands in particular for iodine. The compounds of Formula VII and their stereoisomeric forms are known per se, for example from EP 0 474 561 A1, and can be prepared according to the processes described in this specification or according to analogous processes.
The compounds of Formulae III, IV and VI are known per se or can be prepared by the person skilled in the art from known compounds in known manner. Compounds of Formula IV which are preferentially used comprise D-xylose, D-lyxose, D-arabinose, D-threose, D-erythrose and D- and L-glyceraldehyde.
The compounds of Formula I may be isolated from the reaction mixture and purified in known manner. Acid addition salts may be converted into the free bases in conventional manner, and these may if desired be converted in known manner into physiologically compatible acid addition salts. Physiologically compatible salts of compounds of Formula I are their conventional salts with inorganic acids, for example sulfuric acid, phosphoric acids or hydrohalic acids, preferably hydrochloric acid, or with organic acids, for example lower aliphatic monocarboxylic, dicarboxylic or tricarboxylic acids such as maleic acid, fumaric acid, lactic acid, tartaric acid, citric acid, or with sulfonic acids, for example lower alkanesulfonic acids such as methanesulfonic acid or trifluoromethanesulfonic acid, or benzenesulfonic acids optionally substituted in the benzene ring by halogen or lower alkyl, such as p-toluenesulfonic acid.
The compounds of Formula I contain in the xcex3 position to the ring nitrogen atom in the 4-position of the piperazine ring an asymmetrical carbon atom, namely the carbon atom *C bearing the phenyl ring substituted by R6 and R7. Due to this asymmetric carbon atom and to the asymmetric carbon atom bearing the subgroups A and Z and optionally also due to the asymmetric carbon atoms contained in the subgroup Z, the compounds of Formula I may exist in several stereoisomeric forms. The present invention covers both the mixtures of optical isomers and the isomerically pure compounds of Formula I. Preferred are compounds of Formula I in which the carbon atom *C bearing the phenyl ring substituted by R6 and R7 is in the S-configuration. If mixtures of optical isomers of the starting compound, for example of the compounds of Formula II or the compounds of Formula IV, are used in the synthesis of the compounds of Formula I, the compounds of Formula I are also obtained in the form of mixtures of optical isomers. Departing from stereochemically uniform forms of the starting compound, stereochemically uniform compounds of Formula I can also be obtained. The stereochemically uniform compounds of Formula I can be obtained from the mixtures of optical isomers in known manner, for example by chromatographic separation on chiral separating materials or by reaction with suitable optically active acids, for example tartaric acid or 10-camphorsulfonic acid, and subsequent separation into their optically active antipodes by fractional crystallization of the diastereomeric salts obtained.
The compounds of Formula I and their acid addition salts have properties which are antagonistic to tachykinin receptors and are therefore suitable for the treatment of pathological conditions in larger mammals, particularly humans, in which tachykinins are involved as transfer agents. The group of compounds according to the invention is distinguished by a particularly beneficial activity profile which is characterized by a high selective affinity to NK-2 receptors. Furthermore, the group of compounds according to the invention is distinguished by good compatibility even over prolonged periods of administration, and by comparatively good oral availability. Due to their activity profile, the compounds of Formula I are suitable in particular for inhibiting processes in which tachykinins, such as neurokinin A, which bind to NK-2 receptors are involved. Due to the action which is advantageously directed at the peripheral region, the compounds of Formula I are suitable in particular for the treatment and/or prophylaxis of functional or inflammatory disorders in the gastrointestinal tract of larger mammals, particularly humans, of both sexes, which involve increased sensitivity to pain and/or impaired stool passage in the colon region. The functional disorders in the gastrointestinal tract which can be treated by the compounds according to the invention include in particular the disorders of the lower intestinal tracts known under the name xe2x80x9cirritable bowel syndromexe2x80x9d (=IBS). Typical symptoms for the diagnosis of IBS are described, for example, in W. G. Thompson et al., Gastroenterology International 2 (1989) 92-95 or in W. G. Thompson et al., GUT 45/II (1999) II43-II47, and are generally known among experts by the term xe2x80x9cRome Criteriaxe2x80x9d. The essential symptoms of IBS accordingly include pains in the lower abdomen, which appear to be due to hypersensitivity of the visceral afferent nervous system, and anomalies in bowel movement, such as constipation, diarrhea or alternating constipation and diarrhea. Further inflammatory disorders in the gastrointestinal tract which can be beneficially influenced by the group of compounds according to the invention are for example the inflammatory disorders in the small intestine and large intestine regions usually covered by the term xe2x80x9cinflammatory bowel diseasexe2x80x9d (=IBD), for example ulcerative colitis or Crohn""s disease. Due to their mechanism of action, the compounds according to the invention furthermore appear suitable for the treatment of other disorders in which tachykinins and in particular neurokinin A are involved as transfer agents. These disorders include for example neurogenic inflammations, inflammatory joint diseases such as rheumatic arthritis, asthmatic complaints, allergic disorders, disorders of immune regulation, bladder inflammation or also functional dyspepsia.
Description of the Pharmacological Test Methods
The example numbers given for the compounds of Formula I used as test substances in the pharmacological tests given below relate to the following preparation examples.
1. Determination of the Binding Power of the Test Substances to NK-2 Receptors in vitro
The affinity of the test substances to human NK-2 receptors was measured in vitro. The ability of the test substances to displace the selective NK-2 receptor antagonist SR 48968 (=saredutant) used as reference ligand from its corresponding bond was determined.
The receptor binding studies were carried out with radioactively marked [3H]-SR 48968 (from Amersham) as ligand. For the binding test, different samples of a membrane preparation of CHO cells (=egg cells of the Chinese hamster, Chinese hamster oocytes), which express the human NK-2 receptor (for preparation, see N. P. Gerard et al., Journal of Biological Chemistry 265/33 (1990) 20455-20462), were incubated for 90 minutes (=min.) with a solution of the marked ligand, with the incubation mixtures containing no test substance or additions of different concentrations of test substance. Then in each case the membrane-bound ligands in the samples were separated from free ligands by filtration. The fraction remaining in the filter was washed several times with buffer solution, before its radioactivity was measured using a liquid scintillation counter. That concentration which effects half-maximum displacement of the bound reference ligand was determined as IC50 of the respective test substance. The inhibition constant (Ki value) of the test substance was calculated from the respective IC50 value, and was stated as the negative logarithmised value thereof (pKi).
For the compounds of Examples 1 to 39, the affinity to human NK-2 receptors was determined in each case by at least three measurements of the test substances in concentration series of 10xe2x88x926 to 10xe2x88x9210 mol/l. If several measurements were performed, the average thereof was listed each time. All the aforementioned test substances exhibited pKi values of at least 7.0 in this test model. The compounds of Examples 1 to 27 and 39 exhibited pKi values of at least 8.0. The compounds of Examples 1 to 6 and 39 exhibited pKi values of at least 9.0.
2. Determination of the Functional Antagonism of the Test Substances on Isolated Guinea Pig Tissue in vitro
The NK-2 receptor-antagonising action of the test substances was determined on isolated gall-bladder preparations from Pirbright-White guinea pigs, held in an oxygen-saturated nutrient solution. To this end, the preparations were fastened on one hand in the nutrient solution to organ holders and on the other hand on a force meter by a thread.
In this test the NK-2 receptors present in the gall-bladder preparations were stimulated with the natural NK-2 receptor agonist neurokinin A (=NKA; 0.1 xcexcmol/l) and the contractions of the preparations caused thereby were measured as contractility in mN (=preliminary value) measured. Then NKA was rinsed out of the preparations with NKA-free solution and the test substances were added in a concentration of 10xe2x88x927 mol/l. After two hours"" incubation of the preparations with the test substances, the contractions of the preparations then still caused by renewed NKA addition were again measured and the results were given as percentages, relative to the contractions initially measured, caused solely by NKA addition. The concentration of the test substances was increased iteratively in the subsequent experiments as a function of the result in logarithmic whole or half steps, until at least one concentration above or below 50% inhibition of contraction was determined (up to at most 10xe2x88x925 mol/l). For each concentration, the average value of inhibition of contraction was calculated from 2 to 4 preparations. In each case, the concentration of half-maximum inhibition (IC50) per test substance was calculated as characteristic variable. In each case the logarithmised value of the IC50 per test substance is given as pIC50 in [mol/l]. In this test model, the test substances set forth in Table 1 below exhibited the pIC50 values given below.
3. Determination of the NK-2-receptor-antagonistic Effectiveness of the Test Substances in vivo
The NK-2- and NK-1-antagonistic activities of the test substances were investigated in anaesthetised guinea pigs in each case after intravenous (=i.v.) and oral (=p.o.) administration in vivio. With the present test model it is possible to detect both NK-2-antagonistic effects in three different organ systems (respiratory tracts, colon and circulation) and NK-1-antagonistic effects (rapid drop in blood pressure) in an animal simultaneously.
Pirbright-White guinea pigs of a body weight of 500-700 g were anaesthetised with ketamine/xylazine (67/13 mg/kg subcutaneously, initial dose, further doses administered as required). The animals were provided with an intravenous catheter in order to administer the substance and an intra-arterial catheter to measure the blood pressure. The animals were artificially ventilated via a tracheal cannula and the respiratory pressure was recorded by means of a pressure transducer. A balloon was introduced into the distal colon of the animals for manometric recording of colon motility by means of a pressure transducer. Blood pressure, heart rate, respiratory pressure and colonic pressure were measured continuously for each animal and plotted on a recorder and by means of a digital data-processing system. Neurokinin A (=NKA; 200 pmol/animal) was administered i.v. as a bolus as a test stimulus to stimulate the NK-1- and the NK-2 receptors. An addition of NKA of this type results in a great increase in respiratory pressure (bronchoconstriction) and colonic pressure, and in a biphasic drop in blood pressure. The first phase of hypotension (=phase of maximum hypotension within the first minute after administration of NKA) is mediated via NK-1 receptors, since they can be blocked completely by specific NK-1 receptor antagonists. The second phase of delayed hypotension (=phase of maximum hypotension after 2-5 min.) on the other hand is mediated via NK-2 receptors, since they can be blocked by specific NK-2 receptor antagonists. The doses of the test substances are given as ED50 values which each result in a response to the NKA test stimulus which is reduced to 50% of the initial value, as characteristic variables for the individual measurement parameters bronchoconstriction, colonic pressure and change in blood pressure mediated by NK-1 or NK-2.
The antagonistic effects of the test substances were first investigated in cumulative form, the time of the NKA test stimulus being 1 min. after the administration of the respective doses of the test substances had ended. These ED50 values obtained from cumulative dose effect curves are plotted in Table 2 (line 1) below. In order additionally to detect the variation over time of the antagonistic effects of the test substances, the action of the NKA test stimulus was determined at different times (1, 30, 60, 90, 120, 150 and 180 min.) after administration of the test substances. The antagonistic effects of the test substances were then determined as xe2x80x9carea under the curvexe2x80x9d (xe2x80x9cAUCxe2x80x9d) over the investigation period after administration of the test substances (i.v.: 120 min. after administration: p.o.: 180 min. after administration) and the ED50 values obtained therefrom were listed in the following Table 2 (lines 2 and 3).
The measured values listed in the foregoing Table 2 show, inter alia, that the substances of Examples 1, 5, 13, 14 and 15 after cumulative administration i.v. (detection of the antagonism 1 min. after the administration of test substance had ended) caused a marked NK-2-receptor-antagonistic activity of colon motility, late drop in blood pressure and respiratory resistance.
The measured values plotted in Table 2 also show that the aforementioned substances, in particular the substance of Example 1, caused more effective inhibition of the NK-2 mechanisms at the colon (colon preference) compared with the inhibition of the bronchoconstrictive or hypotensive NK-2-effects. The compounds according to the invention, in particular the substance of Example 1, are furthermore distinguished by a slow-onset action of long duration.
An NK-1-receptor-antagonistic action could not be observed for any of the investigated test substances at the doses used in vivo.
The compounds of Formula I may be administered in conventional pharmaceutical preparations. The doses to be used may vary individually and will naturally vary according to the type of condition to be treated and the substance used. In general, however, medicinal forms with an active substance content of 0.2 to 200 mg, in particular 1 to 50 mg, active substance per individual dose are suitable for administration to humans and larger mammals. The compounds may be contained according to the invention, together with conventional pharmaceutical auxiliaries and/or carriers, in solid or liquid pharmaceutical preparations. Examples of solid preparations are preparations which can be administered orally, such as tablets, coated tablets, capsules, powders or granules, or alternatively suppositories. These preparations may contain conventional pharmaceutical inorganic and/or organic carriers, such as talcum, lactose or starch, in addition to conventional pharmaceutical auxiliaries, for example lubricants or tablet disintegrating agents. Liquid preparations such as suspensions or emulsions of the active substances may contain the usual diluents such as water, oils and/or suspension agents such as polyethylene glycols and the like. Other auxiliaries may additionally be added, such as preservatives, taste correctives and the like.
The active substances may be mixed and formulated with the pharmaceutical auxiliaries and/or carriers in known manner. For the production of solid medicament forms, the active substances may for example be mixed with the auxiliaries and/or carriers in conventional manner and may be wet or dry granulated. The granules or powder can be poured directly into capsules or be pressed into tablet cores in conventional manner. These may be coated in known manner if desired.